Limit-gage.



No.793,620. BATENTED JUNE 27, 1905.

' A. A. BAILLEY.

LIMIT GAGE.

APPLICATION FILED JULY 29, 1904.

Patented June 27, 1905 PATENT FFIQE.

ALBERT A. BAILLEY, OF OOHOES, NEW YORK.

LIMIT-GAGE.

SPECIFICATION forming part of Letters Patent No. 793,620, dated June 27,1905. Application filed July 29, 1904. Serial No. 218,725.

To all whom it may concern:

Be it known that I, ALBERT A. BAILLEY, of Cohoes, in the county ofAlbany and State of New York. have invented certain new and usefulImprovements in Limit-Gages; and I hereby declare that the following isa full, clear,

and exact description thereof, reference being had to the accompanyingdrawings, which form part of this specification.

This invention is an improvement in measuring instruments or limit-gagesfor use in the manufacture or selection of. interchangeable parts ofmachines.

The ordinary limit-gage is simply a piece of metal with two openings init, or two diameters, one slightly larger than the size of the piece tobe gaged and the other slightly smaller. If a finished piece will enteror lit the larger part of the gage, but will not enter or lit thesmaller part, it is considered acceptable, although different pieces oflike form and intended to be used interchangeably may not be exactlyalike measured by a micrometer.

The object of the present invention is to simplify the gages byrequiring but one opening or diameter or length of gage and to providesuch a gage with a yielding adjustable part which can be fixedly set toa predetermined measurement, such as the exterior or interior length ordiameter of a certain object, and also without altering its adjustmentwill allow a limited variation in the size of such objects, such as willnot affect their practical interchangeability, so that the workman usingthe gage will not lose time in measuring to an absolute scale, and yetcannot make such variations in measurement as will affect the practicalinterchangeability of the parts. For this purpose the device has asize-adjusting means and a limit-adjusting means, the latter being anautomatically-adjustable contactpoint which can slightly yield topressure, and anything which will fit closely between the contact-pointsof the size and limit indicators will be serviceable and interchangeablewith other similar parts of like dimensions, although one may and theother may not cause the limit-gage to yield.

In my limit-gage no absolute measurements and gradations for theallowable variation regulator are required. This device moves betweentwo fixed limitsthat is, its possible extent of movement is definitelylimited in both directions, and the distance between these fixed limitsdetermines the extent of possible practical variation of similarobjects, although these may diifer in size if measured by a micrometer.The workman, however, does not have to note any scale or index, asnecessary in using a micrometer-gage.

I Will now explain the device in detail in connection with the drawings,which illustrate several modifications or variations of the device toshow its adaptability to measuring different objects, and refer to theclaims appended to the description for concise summaries of the featuresand parts for which protection is desired.

In the accompanying drawings, Figure 1 is a side View of a gage, partlyin section, adapted for interior or linear measurements. Fig. 2 is asimilar view of a gage especially suitable for exterior or diametricalmeasurements. Fig. 3 is a detail section of a slight modification. Fig.4 is a detail showing the manner of adjusting the outside gage.

The body of handle portion may be straight, as in Fig. 1, or curved, asin Fig. 2, its shape being varied according to the particular design oruse of the gage. To one end of the body is attached an adjustablesize-regulating rod or bar, and to the other end thereof is attached theadjustable limit or allowable-variation regulator. As shown in Fig. 1,the size-regulating device G is a rod or bar of metal, which is threadedon one end, as at g, to engage a correspondingly-threaded socket in oneend of the body or handle A and is locked by a jam-nut H, screwed onpart g and abutting against the end of the body. The locking deviceshown in the drawings is probably the most simple. Any other lockingdevice can, however, be substituted. To the opposite end of the handleor body A is attached the allowablevariation regulator. As shown, thiscomprises a ball 0, confined in a cylinder B, the outer end of which isslightly contracted, so as to prevent escape of the ball while allowingit to slightly project therefrom. The ball is pressed forward by aspring E, which is interposed between the body A and a follower D andsurrounds the stem (Z, attached to the follower at one end and havingits inner end guided in a small recess D in the body, the depth of thisrecess and the adjustment of the cylinder B determining the extent orlimit of variation in size of the objects to be measured by the gagewhile remaining practically interchangeable. The cylinder B, as shown inFig. 1, is exteriorly threaded on one end and screwed into aninternally-threaded socket in the body A, and it can be slightlyadjusted (thereby varying the size measurement) by screwing it in orout, and it can be locked when adjusted by a jam-nutF thereon, asindicated in the drawings. This particular tool is useful for measuringinternal dimensions, but is notrestricted to such particular use.

As shown in Fig. 2, the handle or body A is arc-shaped and thesize-adjusting rod G is tapped through a threaded opening a :in one endof the handle and can be locked when adjusted by the jam-nut H. Theother end of the handle is provided with a cylindrical chamber B inaxial alinement with part G, and a ball 0 is confined in the inner endof this chamber, just as the ball 0 in Fig. l, and is pressed forwardyieldingly by a spring E strung on a stem d between the follower D and aplug I, screwed into the outer end of the chamber B and provided with ajam-nut F. The rear end of stem (2 is seated in a recess H in plug I andlimits the allowable variation in measurements between the point of rodG and the ball C. This tool ismore particularly adapted for measuringthe external sizes of objects. The rod G or G may be of any desiredlength to suit the work, or interchangeable rods of different lengthscan be used with the same body.

As shown in ,Fig. 3, instead of the ball 0 or C a protruding knob orhead C is formed on the follower and takes the place of the ball.

It will be observed that Figs. 1, 2, 3 show different modifications ofconstruction of the allowable-variation regulator or device controllingthe possible practical variation in sizes of interchangeable parts.

The device may be used in manufacturing or selecting interchangeableparts of machines where it is not essential that such parts be of thesame dimensions with mathematical exactness. The device should be set sothat the distance between the points of the bar G or G and the ball orhead G, C, C (according to which form is used) shall be one extreme ofmeasurement, and this, less the distance which the ball or head canrecede, is the other extreme, the limit of possible allowable variationbeing determined by the amount of play allowed the ball or head.

Operation: Themode of using this gage, or

' rather setting the gage for use, is various, ac-

cording to the equipment and facilities at hand of the user. The properway is to adjust the gage for limit first, then for size. This can bedone as follows: Using a micrometer, caliper the two extremitieslightly, note the size on the micrometer, then caliper tight, causingthe plunger to recede and strike bottom (which can be readily felt) andnote differences in measurement. If more or less limit is required,screw limit end in or out, as the case may be, and lock in place. Thenadjust size rod or bar until largest (in the case of internal)-orsmaller (in the case of external) allowable size is obtained, caliperinglightly.

Many shops are provided with a twentyfour-inch micrometer ormeasuring-machine. If, however, it is necessary to set the inside gageto any size beyond the capacity of the micrometer at hand, an extrashort bar-can be used in setting for limit and then be replaced by theproper rod, which can then be set for size, using a sample of the workor a pair of calipers or anything mostavailable. The outside gage can beset for limit with a small micrometer bycalipening over the extremitiesof C and I, as shown in Fig. 4.

This tool can be' used with or without limit, and although it may be setfor a certain amount of limit it can be used to measure to an absolutescale, if desired. As a limit-gage it has the advantage of havingthelargestand smallest allowable sizes embodied in a single tool, therebysaving time and cost of using two separate tools 'or double end gages.As a limit-gage it has the advantages of being adjustable for limit aswellzas for size. It can be set to any given size and used as a fixedgage. Another feature is that the internal limit-gage is self-centering.In measuring the diameter of a round hole-ordinary calipers or a fixedgage will often stick or bind when not'held perfectly central,especially when the hole is nearly finished to size. This gage will,however, readily find the center.

Having thus described my invention, what I therefore claim as new, anddesire tosecu-re by Letters Patent thereon, is-- 1. A limit-gage todetermine within allowable variations the dimensions of similarinterchangeable objects having one relatively fixed terminal, a hollowchamber at its other terminal in axial ali-nement with the fixedterminal, and an allowable-variation regulator in said chamber,comprising a yielding point or contact projecting from one end of suchchamber and movable directly toward or from the fixed terminal, saidcontact being movable only between two fixed limits which determine thepossible allowable variations in dimensions of similar interchangeableobjects, and a spring for holding the-contact normally in one extremeposition, substantially as and for the purpose described.

2. In a measuring device, the combination of a handle, a size-regulatingrod having a threaded engagement with one end thereof,

an allowable-variation regulator on the other end of said handlecomprising a contact movable between two fixed limits which determinethe possible allowable variations in di mensions of similarinterchangeable objects, a spring-actuated follower for pushing thecontact outwardly, adjustable means for varying the limit of movement ofthe regulator, and means for locking said adjusting means, substantiallyas described.

3. In a measuring device, the combination of a handle, a size-regulatingrod having a threaded engagement with one end thereof, and a jam-nut forlocking said rod; acontact loosely attached to the other end of saidhandie and movable between two fixed limits which determine the possibleallowable variation in size of like objects, a spring-actuated followerfor pushing the contact outwardly,.

adjustable means for varying the limit of movement of the regulator, andmeans for locking said adjusting means, substantially as described.

In testimony that I claim the foregoing as my own I aifix my signaturein presence of two witnesses.

ALBERT A. BAILLEY. In presence of FREDK. W. J. MGKIBBIN, GRACE ToMPiuNs.

